Introduction: The present study aimed to investigate the effect of Enterococcus faecium EF55 on chickens, as well as its influence on proliferative activity of epithelial intestinal cells after infection with Salmonella enterica serovar Enteritidis phage type 4 (SE PT4). Moreover, the length and area of duodenal and jejunal villi of the birds were examined.

Domestic poultry is a natural reservoir of Campylobacter, the host–pathogen interaction being predominantly asymptomatic. This study investigated whether chickens remain asymptomatic partly because of lactic acid bacteria (LAB).

Introduction: The main problem in poultry farming is the difficulty in producing food of animal origin without using antibacterial agents. Because most antibacterial compounds are dispensed in water, some water supply systems can be contaminated by antibiotics which are then administered to the animals unintentionally. This can lead to unexpected increases in antibiotic residues in food of animal origin. The aim of the present study was to determine whether the constant exposure of chicken broilers to enrofloxacin affects the withdrawal time of a therapeutic doxycycline that is intentionally administered to the chickens.

Introduction: Avian pathogenic Escherichia coli (APEC) is a leading cause of extraintestinal infection and heavy economic losses. Imparting immunity after vaccination with live attenuated strain vaccination is an ideal strategy for infection control. This study considers an FtsK knockout mutant strain as a candidate. Material and Methods: An FtsK knockout mutant of APEC strain E058 was constructed and the pathogenicity of the mutant and wild-type strains was further evaluated in chickens. Results: The 50% lethal doses of each strain for one-day-old specific-pathogen-free (SPF) chickens challenged experimentally via trachea were 105.5 and 107.0 colony-forming units (CFU) respectively. Chickens challenged with the wild-type strain exhibited typical signs and lesions of avian colibacillosis, while those inoculated with the mutant strain showed mild pericarditis and pulmonary congestion. The growth rate of the FtsK mutant strain was much slower than the wild-type strain in the heart, spleen, liver, and lung of infected chickens. Conclusion: These results indicated that the APEC FtsK mutant can be attenuated for chickens, and that this mutant has the potential for the development of an APEC vaccine.

This study was carried out on serum samples collected from broiler breeder chicken flocks vaccinated with avian influenza (AI) H5N1 inactivated vaccine. These flocks included 23 flocks aged 13 to 47 weeks reared in close houses in 7 sites; two vaccinated breeder flocks for HI antibody monitoring by 5 weeks interval samples and 8 flocks aged 41 weeks reared in different sites with identified females and males samples. The vaccine was used in a dose of 0.2 ml at 1 day in hatchery and revaccinated with 0.5 ml at age of 18 days, 19- 20 weeks and 40 weeks. Hemagglutination inhibition (HI) test was carried out against homologous antigen. The study pointed out that AI H5N1 inactivated vaccine under field application induced irregular and low HI titres following the 1st two doses ranged from log 2 0.0 to 4.15 with great variation between flocks, where samples with titre 0-2 ranged from 20 to 100%. The 3rd dose at 19-20 weeks was essential to elevate HI titres 3.25 to 7.44 with more homogenizes flock immunity and lower percentage of titres 0-2 ( 0-20 %) and as measured by HI test. Revaccination of layer flocks at 40 weeks (fourth dose) improves flock immunity facing stress of egg production as evaluated by HI (5.52 - 6.33) and lower negative percentage (5.5-11.7%). Monitoring of breeder flock every 5 weeks is essential to detect proper time of revaccination as each flock has its HI antibody curve. There was a difference in HI tit re rang log 2 0.33 to 1.2 between male and female chicks reared in the same house, but this variation not affecting flock mean. Birds at aged 41 weeks having titres < log2 3 (Seronegative) were protected when exposed to contact with infected flock as showed no clinical signs or change in HI titres after 12 days. In conclusion the usage of homologous inactivated H5N1 vaccine in 4 doses in layer flocks was of value in improving chicken immunity to AI H5N1 wild strain circulate in our field

The pathogenic effect of representative local isolates of Aeromonas organisms was studied on 1٠0 native breed chickens. At 2 weeks of age, one hundred chicks were grouped into four equal groups (1-4); 25 birds each; after collection of fecal from all groups, examined and proved to be free from Aeromonas species. All groups were subcutaneously (s.c) inoculated with 0.5 ml containing 9×105 cfu /bird. Group 1 of chickens was infected by A. hydrophila; while group 2 was infected with A. caviae. The third group was infected with A. sobria; while, chicks of Group 4 were kept as non infected control. Results were showed mild clinical signs in some birds in theform of alternative diarrhea. Post mortem lesions showed general congestion of all carcasses. In severely emaciated cases the lesions were confined to the intestine, which filled with watery fluid and distended with gas. Results of Aeromonas reisolation revealed that all collected weekly fecal swabs were positive. While, percentage of A. hydrophila and A. caviae was 100% out of all testedorgans, while isolation of A. sobria was 100%, 100% and 80% from liver, intestine and heart; respectively. Histopathological examination of infected chicken organs showing focal coaggulative necrosis in liver with mononuclear cells infiltration that varied in severity between groups as less severe in A. hydrophila (Gr.1) than A. caviae (Gr. 2), while A. sobria (Gr. 3) was markedly affected showing severe degenerated and dissociated hepatocytes. Intestinal changes were severe in group 3 than 2 while group 1 showing the mildest comparatively the changes was consist of necrosed mucosa, gland with leucocytic infiltration in lamina propria. Under thecondition of our study we can conclude that the used Aeromonas isolates from field diseased chickens were of mild pathogenicity to s.c. inoculated 12 days old Fayoumi chicks with long course affection.

This study was done to evaluate susceptibility, protective titer level of maternal derived antibodies(MDAbs) of different chicken breed against virulent Infectious bursal disease virus (IBDV) local isolate Fy97 and prediction the optimal time for vacction. All breeds were experimentally infected orally with IBDV isolate Fy97 every 5 days following detection of MDAbs by ELISA. Clinical signs, mortality, lesions and Bursal Histopathology and lesion score were taken as criteria for comparison. Morbidity rates were observed as ≥ 30% in Fayoumi and Dandrawi infected at 15 days of age and in Senawi and Baladi and Lohmann at 20 days of age All breeds showed clinical sings of infection at 30-35 days of age where Senawi breed showed the highest values (65and 70%) followed by Fayoumi (55 and 55%), Dandrawi (50%), Baladi (55-45%) and Lohmann (50-45%). Mortality rates due to IBD infection varied from 0 to 35% in respective to age, in Fayoumi and Lohmann breeds where maximum 35 and 40% occurred at 30 day of age; respectively .Mortality in Dandrawi and Senawi varied from 5 to 40% and pass in close manner at all intervals with the highest value at 30 days of age while Baladi chicks showed same values but lower only at 20 and 25 days. Mean lesion scores in Fayoumi were the lowest at all intervals followed by Lohmann, Senawi, Baladi and Dandrawi. Results of ELISA titers at time of infection showed that Senawi chicks having the highest titers followed by Lohmann, Baladi, Dandrawi and Fayoumi at most intervals. So it necessitates more clarification of the causes of these phenomena and the role of genetics in protection against IBDV infection.

A total of 90 one-day-old male broiler chicks were fed on balanced ration for 15 days and then divided into 3 equal groups. Control group fed ration probiotic free, group 2 and 3 fed ration supplemented with probiotic at concentration levels 0.5 and 1.0g/kg ration respectively for 4 weeks.It was found that probiotic improve body weight gain and feed conversion ratio. Relative organs weights were not altered in groups of birds fed ration mixed with probiotic. Serum values of biochemical parameter (AST, ALT, ALP, total protein, A/G ratio, Ph) were not significantly changed in comparison to control group. Probiotic enhance the immune response of broiler chickens in a dose dependent relation as documented by increasing the serumNDHI antibody geometric mean titres to ND vaccine, phagocyte percentage and phagocytic index of peripheral blood monocyte of broiler chickens. We concluded that probiotic composed of 3 strains of bacteria (Pediococcus acidilactici, Pediococaoccus pentosaceus and Bacillus Amylolique- faciens) in addition to 2 strains of yeast( Pichia farinose and Dekera anomala ) enhance body weight gain, feed conversion, growth performance and Newcastle disease antibody titres in broiler chickens. Moreover, probiotic was safe as proved by serum biochemical profile and relative organ weight of male broiler chickens.

In 9 weeks field study, a total of 14100 (Ross broiler breeders) 51 weeks-old chickens fed on the same ration, placed in 2 houses (6600 female + 450 male / house). Birds of house 1 were treated with antimycotoxin adsorbent aluminum silicate (G-V-tox®) 5 kgm/ ton, while those of house 2 were kept as non treated controls. Productivity and reproductivety parameters were calculated for comparison. Treated flock showed improved average egg production (Average 62.2%/week) compared with non treated (Average 61.7%/week), but all still lower than farm stander (Average 76.4%/week). Marked improvement was in the 1st 3 weeks (51-53) of treatment only. Total 9 weeks production declined was 5.5% and 8.4% in control and silicate treated flock; with weekly average of 0.61, and 0.93; respectively. Control flock was slower in decline of production (0.61%/week) than treated flock (0.93%/week). Average weekly egg production and hatching eggs/ hen in treated flock was lower than standard and higher than non treated. Hatchery parameters of treated were improved in treated at the first 3 weeks post treatment. The fertility was higher in aluminum silicate treated group (77.2%), than the untreated one (72.19%). The hatchability was in silicate treated (63.66%) versus (62.25%) in the untreated control. Culls % in hatched chicks was 1.91% in treated flock and lower than in non treated (2.85%). Difference percentage between fertility and hatchability of G.V. tox treated chickens was (10.84%) higher than untreated control (16%). The number of marketable chicks l100 was also improved in treated than non treated. In conclusion, our field study cleared that administration of Silicate in ration for treatment of broiler breeders resulted in an improved production and hatchery performance as compared with non medicated control. However; it did not restore it to the farm stander. Consequently the results indicated that we still in need for more effective products to be used to control mycotoxins in breeder chicken.

The pharmacokinetic profile and some pharmacodynamic aspects of cefquinome were studied after intramuscular (IM) and subcutaneous (SC) administration of a single dose of 2 mg kg-1 b.wt. in chickens. Tissue distribution and residues of cefquinome after repeated IM injection for 5 consecutive days were also estimated. Cefquinome was rapidly absorbed after IM and SC injection as indicated by short half-lives of absorption (t0.s(ab)) of 0.170 and 0.262 h., respectively, while the elimination half-lives (t05(el)) were 3.428 and 25.023 h., respectively. Repeated IM doses of cefquinome (2 mg kg-1 b.wt., once daily) for 5 consecutive days caused no change in serum enzyme activities of ALT and AST, but induced significant increase in serum uric acid concentration after 72 to 120 hours of administration. The withdrawal time of cefquinome from tissue of chickens is 5 days following the last dose. Cefquinome has a wide spectrum of activity against Esherchia coli, Proteus mirabilis and Pseudomonas aeroginosa.